NO750307L - - Google Patents

Description

"Procedure for internal gluing of a cellulose material, as well as adhesive for carrying out the method".

This invention relates to internal or internal gluing of paper and other cellulosic materials under pH conditions from moderately acidic to strongly alkaline. The method according to the invention comprises internal gluing of the cellulose material by means of a gluing agent and a retention agent, and the method is characterized in that the internal gluing agent is a water-dispersible, water- and alkali-insoluble copolymer of an α, (3-ethylenically unsaturated hydrophobic monomer and a ammoniated a,p-ethylenically unsaturated carboxylic acid and the retention agent is a water-dispersible reaction product of epihalohydrin and ammonia, an alkylamine or an aliphatic pblyamine with at least two amine hydrogen atoms per molecule or a mixture of ammonia and the alkyl and/or polyamine . According to a preferred embodiment, rosin and alum are added to the cellulosic material to improve the gluing effect of the internal adhesive and retention agent. The invention also provides an adhesive for cellulosic materials, which adhesive contains an adhesive amount of the above-mentioned copolymer and an amount of the said retention agent sufficient to hold the copolymer on the cellulose material.. The invention further provides a cellulose material which is internally glued with the above-mentioned glue. The resulting internally glued cellulose material exhibits a very desirable degree of resistance to water as well as resistance to acidic and alkaline solutions. Of particularly large. significance is that the use of the above-mentioned copolymers as a bonding agent in combination with the above-mentioned cationic retention agent is not limited to pH values on the acidic side, so that the aforementioned bonding agents can be used when treating neutral and alkaline wood pulp as well as acidic wood pulp. Furthermore, it has been found that even moderate drying and curing conditions are sufficient for full utilization of the aforementioned adhesives and satisfactory

silent gluing.

The term "cellulosic material" here includes paper and other fibrous, sheet-like or shaped masses derived from wood, wood pulp or cotton or other cellulosic fiber starting materials. This expression also includes sheet-like or shaped masses produced by the combination of cellulose materials and other materials such as, for example, polyamides, polyesters, polyacrylic acid fibers and mineral fibers such as asbestos and glass.

The term "internal gluing" or "internal gluing" means a method where the cellulose material in its raw state, e.g. wood pulp for papermaking, is brought into contact with the glue under such conditions that the cellulose material is glued, i.e.

. that the glue is deposited on the fibers and hardens under full gluing effect. The aforementioned expression is intended in a broad sense and includes

therefore, for example, beater-sizing, machine-sizing and internal wet-end sizing ("beater-sizing", engine-sizing" and "internal wet-end sizing").

The glue which is suitably used in carrying out the present invention are copolymers of a,p-ethylenically unsaturated hydrophobic monomer and ammoniated a,p-ethylenically unsaturated carboxylic acid, i.e. a,p-ethylenically unsaturated carboxylic acid in the form of the ammonium salt. Such copolymers are usually semi-solid or solid materials that can be dispersed in water. The copolymers have molecular weights that give melt flow viscosities in the range from approx. 0.2 decigrams/minute, measured according to ASTM D-1238^65T(E) to approx. 50 decigrams/minute measured according to ASTM D-1238-65T(B), with the exception that the nozzle opening in the extrusion plastometer is 0.5 mm. Preferably, the copolymer has an average molecular weight, determined ebulliometrically, within the range of 1000-10000 and a melt flow viscosity within the range of 0.5-50 decigrams/minute determined in accordance with ASTM D-1238-65T(B) using said plastometer with nozzle opening of 0.5 mm. Preferred \kopo\Lymers are also film-forming at the temperatures used during gluing. The term "water-dispersible" means a material which can exist in the form of a stable, aqueous, colloidal dispersion without the use of a surface-active agent. In the form of aqueous dispersions, the copolymers preferably form films under normal conditions, which films dry to form a coating which is insoluble in water. By a, |3-ethylenically unsaturated hydrophobic monomer is meant here any monomer which is immiscible with water and which contains a terminal double bond which enables polymerization under normal conditions for addition polymerization to form a water-insoluble homopolymer with a polyethylene main chain. By a,p-ethylenically unsaturated carboxylic acid is meant here an a,p-ethylenically unsaturated carboxylic acid which enables addition copolymerization with the a,p-ethylenically unsaturated hydrophobic monomer by means of the ethylenically unsaturated group. By ammoniated a,p-ethylenically unsaturated carboxylic acid is meant here that the carboxylic acid groups in the copolymer have been neutralized with ammonia.

The adhesive is preferably a normally solid, water- and alkali-insoluble thermoplastic addition copolymer in the form of a flowable aqueous colloidal dispersion. Ammonium acid groups in the polymer should be found throughout the macromolecules, so that each macromolecule contains a minimum number of active salt groups which is sufficient to make the polymer dispersible in water. The maximum number of ammoniated acid groups that can be present in the macromolecules is determined by the requirement that the molecule must be mainly water-insoluble. Such copolymers generally contain from 6 to 40% by weight of ammoniated acid comonomer, with preferred copolymers containing from 10 to 20% by weight of ammoniated acid comonomer and especially preferred copolymers containing from 15 to .18% by weight. . Examples of preferred copolymers are the randomized copolymer products obtained by copolymerizing mixtures of one or more polymerizable ethylenically unsaturated carboxylic acids with 3-8 carbon atoms, including anhydrides and alkyl half-esters, such as, for example, acrylic acid, methacrylic acid, maleic acid and anhydride, itaconic acid , fumaric acid, crotonic acid and citraconic acid and anhydride, roethyl hydrogen maleate, ethyl hydrogen maleate, and one or more a,p-ethylenically unsaturated hydrocarbon monomers, such as, for example, the aliphatic a-olefin monomers, conjugated dienes and fmonqVirv-3 lylidene-arbmatic carboxylic- monomers. Furthermore, other ethylenically unsaturated hydrophobic monomers which are not entirely hydrocarbon monomers can be copolymerized with the above-mentioned acid copolymers. Examples of such suitable monomers include esters of α,β-ethylenically unsaturated carboxylic acids such as e.g. ethyl acrylate, methyl methacrylate, ethyl methacrylate, methyl acrylate,

isobutyl acrylate and methyl furnarate; unsaturated. esters of non-polymerizable carboxylic acids such as vinyl acetate, vinyl propionate and vinyl benzoate; vinyl halides such as vinyl and vinylidene chloride; vinyl ethers; a, (3-ethylenically unsaturated amides and nitriles such as acrylamide, acrylonitrile, methacrylonitrile and fumaric acid nitrile. The hydrophobic monomers can be copolymerized with the preferred hydrocarbon monomer and the acid comonomer in such a ratio that a water- and alkali-insoluble polymer is obtained Preferred copolymers include copolymers of 70-90% by weight ethylene, 10-20% by weight of one or more ammoniated ethylenically unsaturated acids, such as acrylic acid and methacrylic acid and 0-20% by weight ethylenically unsaturated hydrophobic monomer, such as acrylonitrile, ethyl acrylate and vinyl acetate..

Other copolymers which are suitable are prepared from previously formed, non-acidic polymers by subsequent chemical reactions. E.g. the carboxylic acid group can be provided by grafting a monomer such as acrylic acid or maleic acid and a polymer substrate such as polyethylene. Furthermore, copolymers containing carboxylic acid anhydride, ester, amide, acyl halide and nitrile groups can be hydrolysed to carboxylic acid groups which can then be neutralized to the ammoniated carboxylic acid.

It will also be understood that the α,β-ethylenically unsaturated carboxylic acid in the form of the ammonium salt can be copolymerized with the hydrophobic monomer to produce a suitable copolymer.

Methods and means for producing the polymers are known. Preferred low molecular weight copolymers are prepared in a known manner with the exception that a telogen such as propylene is used in the reaction mixture. In cases where the acid copolymer is obtained in the form of a mass, the copolymer can be converted into an aqueous colloidal dispersion and then concentrated and ammoniated. Processes for the preparation of the aqueous colloidal dispersion of a copolymer which require little or no emulsifier or other surfactants are generally preferred. The aqueous, colloidal dispersion of copolymer preferably has a content of polymer in solid form of 5-60% by weight and sufficient stabilizing ammonia to give the dispersion a pH of at least 7.5. - Dispersions with a high content of solids are suitably prepared from dispersions with a low content of solids in a manner known per se.

In order to achieve a degree of gluing that is satisfactory

when producing glued paper (including paper with a high glue content), it is necessary to use the copolymer glue according to the invention in connection with a reaction product of epihalohydrin and ammonia, or an alkylamine or aliphatic polyamine which has at least two amine hydrogen atoms per molecule or a mixture of the amine and ammonia, which in the following summary is referred to as epihalohydrin/amine reaction product. Haze-

se reaction products can be used as co-additives which improve the retention of the copolymer adhesive and which bring the copolymer adhesive into better contact with the fibers of the cellulose materials during gluing. Suitable epihalohydrin/amine reaction products are dispersible in water, preferably soluble in water. Such water-dispersible reaction products have molecular weights in the range

a 200-80000. Preferred reaction products include from 0.9

to 2.1, especially from 1.3 to 1.7, moles of epihalohydrin. per moles of amine, e.g. ammonia, alkylamine, polyamine or mixtures thereof. , The preferred ammonia and/or polyamine reaction products have one or more molecular weight peaks, determined by gel permeation chromatography and such peaks are normally found within the range from 2000 to 70,000. Particularly preferred reaction products are those which exhibit at least one peak within the molecular weight range from 40,000 to 70,000. The preferred alkyl amines have 10-22 carbon atoms in the alkyl chain and the preferred apihalohydrin/alkylamine reaction products have molecular weights in the range of 400-3000.

In the internal gluing of paper and other cellulosic materials using the above-described copolymers as gluing agent, a number of different working methods can be used

is. However, it is of great importance that the working methods used provide an even and uniform dispersion of the glue in the cellulose fiber material during gluing. Uniform dispersion can be achieved by adding the ammoniated copolymer adhesive in a completely dispersed form, e.g. in the form of a watery paste! dispersion.

In order to achieve maximum distribution of the copolymer adhesive on the fiber material and to prevent the copolymer adhesive from clumping,

it is particularly desirable when the epihalohydrin/amine reaction product

et is strongly cationic, to add the glue to the fiber material

before or simultaneously with the addition of the reaction product or shortly afterwards, usually within 30 minutes. The copolymer adhesive is preferably added to the slurry of fiber material before the reaction product is added. No matter which

technique chosen for the addition of the ammoniated copolymer and the epihalohydrin/amine reaction product to the fiber material, one must try to avoid that the ammoniated copolymer comes into contact with the reaction product before it comes into contact with the fiber material.

The actual addition to the cellulose material of either the reaction product or the glue can take place at any point during the production of the cellulose material before the final transformation of the wet fiber material into tissue, sheet or shaped object. By. paper production, you can e.g. add the glue to the wood pulp while it is in the inlet vessel, the Dutchman, the cooker

or the wood pulp tub.

In order to achieve good internal gluing, it is desirable that the ammoniated copolymer gluing agents are distributed evenly in the fiber material in the most finely divided state possible. Such uniform dispersion can, for example, be achieved by dispersing the adhesive in

aqueous media before the addition to the fiber material. As a rule, it is desirable to use the ammoniated copolymer adhesive in an aqueous/colloidal dispersion without emulsifiers and surface-active agents, but such agents can be suitably used in the execution of the invention, provided that they are volatile during gluing or otherwise do not reduce the effectiveness of the copolymer adhesive.

The gluing agents according to the invention are used with very good results for gluing paper made from various types of cellulose fibers and combinations of cellulose fibers and other fibers. The cellulose fibers which can be most advantageously used include bleached and unbleached sulphate (kraft), bleached and unbleached. sulphite, bleached and unbleached soda, neutral sulphite, semi-chemical and mechanical fiber material and any combination of such materials. These designations apply to pulp fibers that have been produced using a number of different processes such as

is known within the paper and pulp industry.

All types of additives, such as pigments, fillers, stabilizers, retention agents, wet strength additives and dry strength additives, as well as further adhesives can be used in combination with the copolymer adhesive according to the invention. Such additives include kaolin clay, talc, titanium dioxide, calcium carbonate, diatomaceous earth, plastic pigments, aluminum trihydrate and precipitated silica. It has been found that the addition of rosin and alum is not effective when CaCC^ is used as a filler, and that alum is not as effective

in the presence of ammoniated epihalohydrin as it is in the presence of amine-treated epihalohydrin. In the most preferred embodiment of the invention, one uses from 0.05 to 2, preferably 0.5-1 parts by weight of alum and from 0.05 to 2, preferably 0.5-1 parts by weight of rosin per 2000 parts by weight of dry cellulose material in which the weight ratio between alum and rosin is from 1:3 to 5:1, preferably approx. 1:1. The ratio between the amount of alum/rosin and ammoniated copolymer adhesive is generally in the range of 0.01 to 4.0, preferably 0.12 to 2.5.

The ammoniated copolymer adhesive is suitably used in amounts adapted to give the desired effect, e.g. water resistance amounts from 0.005 to 20% by weight, based on the weight of cellulose material in the dry state in the final sheet are generally suitable, preferred amounts being within the range of 0.05-2% by weight and particularly preferred amounts being within the range of 0.2 to 1% by weight. Within this numerical range, the exact amount used will depend for the most part on the type of cellulose material, the specific operating conditions and the special intended use for the cellulose material. E.g. want. paper that must withstand water or dyes necessitates the use of a higher concentration of adhesive than a paper with properties that require only smaller amounts of adhesive. Any amount that is appropriate for the desired end result can thus be used.

These same factors also apply in relation to the amount of epihalohydrin/amine reaction product used as retention agent in connection with ammoniated copolymer adhesive. The person skilled in the art will thus be able to use the reaction product and the adhesive in whatever concentrations he finds appropriate under the relevant operating conditions during the above-described gluing of cellulose material. As a general rule, however, the epihalohydrin/amine reaction product is usually used in amounts within the range of 0.5-5 parts by weight per parts by weight of copolymer glue, preferably 1.5-3 parts by weight of react

sion product per weight part copolymer glue.

The following examples illustrate preferred embodiments of the invention. The embodiments marked with xx) are those which are preferred only to a lesser extent. All parts and percentages are by weight unless otherwise stated.

EXAMPLE 1

500 g of a copolymer of ethylene and acrylic acid (87.3/12.7) with a molecular weight peak of 6950, determined by gel permeation chromatography, and a melt viscosity (ASTM D-1238-65T(B) , plastometer nozzle opening 0.5 mm) of 2 decigrams/minute is added to 240 ml of aqueous ammonia (28% NH3) in a 4 liter flask containing 2.94 liters of water. These ingredients are stirred for 8 hours at 100°C and the resulting dispersion is allowed to cool to room temperature. The dispersion is strained through a cloth, whereby clumped material is removed. The resulting filtrate is an aqueous dispersion containing 13.6% ethylene/ammonium acrylate polymer in solid form and which has a pH of approx. 8.

431 g (7 g mol) of 28-30% aqueous ammonia are added to a 5 liter reaction flask equipped with a reflux condenser, stirrer, thermometer and feed funnel and the flask is partially immersed in a cooling bath; while the reaction mixture is kept at a temperature of 16-20°C, 925 g (10 g mol) of epichlorohydrin are added over the course of 4 hours. After the addition is complete, the reaction mixture is stirred for a further 16 hours at the same temperature, after which 330 g of water are added, and the mixture is heated to 100°C and cooled to room temperature within 2 hours. A mixture of 200 parts by weight of this prepolymer resin and 100 parts of epichlorohydrin and 200 parts of water is stirred for 2 hours at 95°-98°C and then cooled to room temperature. The aqueous dispersion of copolymer and reaction product solution was added separately to 236 parts of an aqueous slurry of bleached kraft pulp, which slurry contained 0.33% solids and had a pH of 7.8, which was adjusted to 4, 5 by adding I^SO^. Towels are formed and dried according to TAPPI T-205m-53. The surface wettability to water (contact angle) and dye penetration of the towels is determined and is indicated in the table

IN.

As a further illustration of this embodiment, an adhesive containing different amounts of the aqueous dispersion of the copolymer and the reaction product is used for internal gluing of the above-mentioned wood pulp. In the same way as above, the treated wood pulp is converted into towels, which are tested with regard to wetting and dye penetration. These results are also shown in Table I.

EXAMPLE 2

One. 3.3 kg portion of a copolymer of ethylene and acrylic acid (86/14) with a melt viscosity (ASTM D-1238-65T(B), nozzle opening 0.5 mm) of 2 decigrams/minute (average molecular weight 4,450) is added to 28.4 1 water and 2.3 1 aqueous ammonia (28% NH^) while stirring in a container with a volume of approx. 38 1. The mixture is heated with stirring and kept at 100°C and 3.2 kg/cm^ for 3 hours. The product is decanted and filtered through a 100 mesh stainless steel sieve (with openings of 0.149 mm). A yellowish dispersion containing 10% copolymer in solid form is obtained.

4 parts of the epichlorohydrin/ammonia reaction product used in Example 1 are diluted with 27 parts of water. 2.9 parts of the copolymer dispersion specified above are diluted with 4.8 parts of water. The two dilutions are added separately to a slurry of bleached kraft pulp. The pH of the mixture is adjusted to 3.5 with sulfuric acid. The wood pulp slurry is formed into a towel and tested with regard to dye penetration and the wetting angle for water. The above procedure is repeated using wood pulp slurries with pH values of '4.8 - 6.1 - 7.1 - 7.9 - 9.1 and 10.2. The results of these tests, which are reproduced in Table II, show that the copolymer adhesive is effective over a wide pH range.

EXAMPLE 3

A 40 g portion of a copolymer of ethylene and acrylic acid (89/11) with a melt viscosity (ASTM D-1238-65T(B), nozzle opening 5 mm) of 43 decigrams/minute (average molecular weight 4075) is added to 27 g of aqueous ammonia (28% NH^) and 200 g of water in a 0.5 liter stainless steel bomb reactor. The bomb is sealed and the reaction mixture is shaken for 3 hours at 95°C. The resulting dispersion contains 15% copolymer in solid form.

0.18 part epichlorohydrin/ammonia reaction product as used in Example 1 is diluted with 6 parts water. The resulting solution is added to a slurry of bleached kraft pulp in the ratio indicated in Table III and stirred for 1 minute. 0.19 part of the above-mentioned dispersion of ethylene copolymer is diluted with 7.7 parts of water and is then added as glue to the wood pulp slurry in the ratio indicated in Table III. The pH of the resulting slurry is adjusted to 4.5 with sulfuric acid. The wood pulp is formed into a towel, which is tested with regard to dye penetration and the water's contact angle. The results are reproduced in Table III.

EXAMPLE 4

An aqueous dispersion (11% copolymer in solid form) of ammoniated copolymer of ethylene and acrylic acid (86/14) with an average molecular weight of 4500 is prepared according to the method in Example 1. An aqueous solution of a retention agent as indicated in Table IV is added in amounts as indicated in Table IV to a slurry of bleached kraft pulp (0.3% solids in water) with stirring. The dispersion of ammoniated copolymer is then added to the slurry of the wood pulp with stirring in amounts as indicated in Table IV. The wood pulp slurry is converted into towels, which are dried according to TAPPI T-205m-53. The water wetting (contact angle) and dye penetration of the dried towels are determined. The results are reproduced in Table IV.

For comparison purposes, the procedure is repeated with the exception that a cationic starch is used as retention agent. The resulting towels are examined for surface wetting and dye penetration. These results are also reproduced in Table IV.

EXAMPLE 5

> 22.7 kg copolymer of ethylene and acrylic acid (85/15) with a melt viscosity of 5 decigrams/min. (ASTM D-1238-65T (E)) is added while stirring to 34 kg of aqueous ammonia (28% NH_) 0<3 34 kg of water in a container with a volume of approximately 95 litres. The mixture is kept at 140°C for 5 hours. The excess ammonia is removed at 85°C, after which the product is drained from the container. The resulting dispersion contains 24% copolymer in solid form.

4.0 parts of an epichlorohydrin/ammonia reaction product as used in Example 1 (25% solids) are diluted with 27 parts of water. 0.12 part of the above ethylene copolymer dispersion is diluted with 7.7 parts of water. The two dilutions are added to a bleached kraft pulp slurry in relative amounts as indicated in Table V. The pH of the resulting slurry is adjusted to 4.5 with sulfuric acid and formed into a towel. The hand towel is tested with regard to dye penetration and contact angle when moistened with water and the results are reproduced in Table V.

EXAMPLE 6

3.31 kg copolymer of ethylene and acrylic acid (86/14) with an average molecular weight of 4500 and a melt viscosity

(ASTM D-1238-65T(B)), piastometer nozzle opening 0.5 mm) at 2 decigrams/minute is added to 2.33 liters of aqueous ammonia (28% NH^)

in a 37.8 liter container containing 28.4 liters of water. The mentioned ingredients are stirred for 3 hours at 100°C and 3.2 kg/cm^

and the resulting dispersion is allowed to cool to room temperature. The dispersion is strained through a cloth, whereby clumped material is filtered out. The resulting filtrate is an aqueous dispersion containing 10% ethylene/ammonium acrylate copolymer in solid form.

100 g of octadecylamine dissolved in 100 g of 95% ethanol are added to a 1-litre reaction flask equipped with a reflux condenser, stirrer, thermometer and feeding funnel and heated to 30°C. 44.3 g of epichlorohydrin are added to the flask over 15 minutes, after which the contents of the flask are kept at 100°C for 4 hours. The solvent is removed from the final product in vacuum at a slightly elevated • temperature. The reaction product has an average molecular weight (determined embuliometrically) of 510 and contains the reactants in the form of a condensation product containing 1.4 mol of epichlorohydrin per moles of octadecylamine. An emulsion of the reaction product can be easily prepared by boiling the product in distilled water for a few minutes.

Unbleached kraft pulp of softwood is ground to 425 SCF (Standard Canadian Freeness) in a Dutchman (valley beater) with a consistency of 1.5% according to TAPPI Standard T200 os 70. From the resulting mixture, 100 ml is taken which is diluted to 800 ml at addition of 700 ml of water. While stirring the diluted mixture, 1 ml of a 1%<1>s alum solution (0.66% by weight based on dry wood pulp) is added and the mixture is stirred for 5 minutes. A 3 ml portion of a 0.075% solution of the aforementioned epichlorohydrin/octadecylamine reaction product (0.15% by weight based on dry wood pulp) is added to the wood pulp mixture which is stirred for 3 minutes. A 6 ml portion of the ethylene/ammonium acrylate copolymer latex

(0.3% by weight based on dry wood pulp) is added to the wood pulp mixture containing the reaction product and the wood pulp mixture is stirred again for 3 minutes. The pH of the wood pulp is adjusted to 5 with 0.1 N sulfuric acid, after which the wood pulp is fed to the feed container for a TAPPI sheet former containing 1 ml of 1%<1>s paper machine alum. A number of towels are produced in accordance with TAPPI Stand-

ard T205 os 71. The towels are dried, hardened and conditioned overnight according to TAPPI Standard (T400 os 70) (at 72°C and 50% relative humidity). The towels are tested with regard to water resistance and dye penetration and the results are reproduced in Table VI.

For comparison purposes, a number of samples are prepared according to the method indicated above, with the exception that different amounts of the copolymer glue (e/AA) and epichlorohydrin/amine reaction product (EPl/ODA) are used. A control sample is also prepared (Sample no. C), where no EAA or EPl/ODA is used. Towels are produced using these samples according to the above procedure. The towels are tested and these results are also shown in Table VI.

EXAMPLE 7

The procedure in Example 6 is followed with the exception that other copolymer adhesives are used and a number of samples are prepared using additives in an amount of 0.4% by weight copolymer adhesive and 0.4% by weight epichlorohydrin/octadecylamine. The samples are examined and the results are given in Table VII.

EXAMPLE 8

According to the procedure in example 7 and using bleached kraft wood pulp (50% hardwood, 50% softwood), a number of samples were prepared with varying amounts of additives, as indicated in Table VIII. The samples were tested in the form of towels as indicated in Table VIII, and the results are indicated in the same table.

EXAMPLE 9

500 g of copolymer of ethylene and acrylic acid (87.3/12.7) with an average molecular weight of 6950, determined bulliometrically, is added to 240 ml of aqueous ammonia (28% NH^) in a 4 liter container containing 2.94 liters of water. The ingredients are stirred for 8 hours at 100°C and atmospheric pressure and the resulting dispersion is allowed to cool to room temperature. The dispersion is filtered through a cloth, whereby clumped material is removed. The resulting filtrate is an aqueous dispersion containing 13.6% ethylene/ammonium acrylate copolymer in solid form.

291 g (17.1 mol) of 28% aqueous ammonia are added to a 5-liter reaction flask equipped with a reflux condenser, stirrer, thermometer and feedstock, and the container is partially immersed in a cooling bath. To the reSk's ion mixture, which hp lde1 s at 30-35°C, add 555 g

(6 moles) of epichlorohydrin in the course of 1.5 hours. After the addition is complete, the reaction mixture is stirred for a further 0.33 hours at the same temperature, after which 1000 g of water is added, and the mixture is heated to 60-65°C. The reaction mixture is kept at this temperature and stirred for 2 hours. 1000/ml of water is added to this prepolymer resin. After 10 minutes of stirring, 250 g of 50% NaOH are added, and the mixture is stirred for 30 minutes. Now 151 g of epichlorohydrin are added to the mixture over 10 minutes, and the mixture is kept at 60-65°C for 2 hours. The pH of the mixture is set to 4.0-4.5, after which the mixture is cooled to room temperature.

1 part 0.375% reinforced rosin in water is mixed with

1 part 0.375% alum (aluminum sulphate) in water forming a cloudy stable complex.

Bleached kraft wood pulp from softwood and bleached kraft wood pulp from hardwood are measured in a Dutchman to 425 SCF (Standrard eanadian Freeness) with a consistency of 1.5% according to TAPPI Standard" T200 os 70. Equal parts of the two wood pulps are mixed to a slurry with an SCF of 409. From the resulting mixture, 400 ml is taken and diluted to 1892 ml by the addition of 1492 ml of water. While stirring the diluted mixture, the rosin/alum complex is added in amounts as indicated for Sample No. 1 Table IX , and the mixture is stirred for one minute. A 4.9 ml portion of the above^ 0.375% solution of epichlorohydrin/ammonia reaction product (0.31% by weight based on dry wood pulp) is added to the wood pulp mixture, which is stirred for 30 seconds. A 2.96 ml portion of the ethylene/ammonium acrylate copolymer latex (0.185% by weight based on dry wood pulp) is added to the pulp mixture containing the reaction product and the rosin/alum complex, and the pulp mixture is stirred again for 30 seconds. ter at a pH of 8 added to the feeder in a Noble and Wood sheet forms and towels are prepared. These are dried, cured at 80°C for 30 minutes and conditioned for 4 hours according to TAPPI Standard T400 os 70 (at 23°C and 50% relative humidity). The towels are tested for dye penetration, and the results are shown in Table ( IX: For comparison purposes, a number of samples are prepared according to the above-mentioned method with the exception that other amounts of copolymer adhesive (E/AA), epichlorohydrin/ammonia reaction product (EPl/NH^) and/or rosin/alum complex are used. control samples (samples no. C^-C^), where no rosin/alum complex was used. Towels are prepared using these samples according to the above procedure. The towels are tested, and these results are also given in Table IX.

Claims (24)

1. Process for internal gluing of a cellulose material using an adhesive and a retention agent, characterized in that the adhesive is a water-dispersible, water- and alkali-insoluble copolymer of an a, B-ethylenically unsaturated hydrophobic monomer and an ammoniated a, S-ethylenically unsaturated carboxylic acid, and the retention agent is a water-dispersible reaction product of epihalohydrin and ammonia, an alkylamine or an aliphatic polyamine with at least two amine hydrogen atoms per molecule or a mixture of ammonia and an amine. 2. Method according to claim 1, characterized in that the reaction product has at least one molecular weight peak, determined by gel permeation chromatography, within the range from 2000<rr> to 70,000. 3. Process according to claim 1, characterized in that the reaction product is water-soluble and the /mol ratio between epihalohydrin and amine is from 0.9 to 2.1 mol of epihalohydrin per moles of amine. 4. Method according to claim 1, characterized in that the cellulose material is wood pulp. 5. Method according to claim 1, characterized in that the hydrophobic monomer is an α, β-ethylenically unsaturated hydrocarbon. 6. Method according to claim 5, characterized in that the hydrocarbon is an aliphatic α-monoolefin. with 2-14 carbon atoms. 7. Process according to claim 6, characterized in that the aliphatic α-monoolefin is ethylene. 8. Method according to claim 7, characterized in that the carboxylic acid is acrylic acid. 9. Method according to claim 7, characterized in that the carboxylic acid is methacrylic acid. 10. Method according to claim 7, characterized in that the copolymer is film-forming under the gluing conditions. 11. Method according to claim 10, characterized in that the copolymer has an average molecular weight peak within the range from 1,000 to 10,000 and contains from 10 to 20% by weight of α,β-ethylenically unsaturated carboxylic acid. 12. Method according to one of claims 1-11, characterized in that the cellulose material is glued under pH conditions corresponding to a pH of at least 7. 13. Method according to one of claims 1-12, characterized in that rosin and alum are added to improve the effectiveness of the adhesive and the retention agent. 14. Adhesive for cellulosic materials, characterized in that it contains an adhesive amount of a water-dispersible, water- and alkali-insoluble copolymer of an a,B-ethylenically unsaturated hydrophobic monomer and an ammoniated a,B-ethylenically unsaturated carboxylic acid, where the copolymer contains from 6 to 40% by weight of the ammoniated carboxylic acid, and a water-dispersible reaction product of epihalohydrin and ammonia, an alkylamine or aliphatic polyamine with at least two amine hydrogen atoms per molecule or mixture of ammonia and the amine in an amount which effectively acts to hold the copolymer on the cellulosic material. 15. Agent according to claim 14, characterized in that the reaction product has at least one molecular weight peak, determined by gel permeation chromatography, within the range from 2,000 to 70,000. 16. Agent according to claim 15, characterized in that the reaction product is water-soluble and the mole ratio between epihalohydrin and amine is from 0.9 to 2.1 mol of epihalohydrin per moles of amine. 17. Agent according to claim 14, characterized in that the hydrophobic monomer is ethylene <p> and the carboxylic acid is acrylic acid. 18. Agent according to claim 14, characterized in that the hydrophobic monomer in the copolymer is ethylene. 19. Agent according to one of clauses 14-18, characterized in that it contains rosin and alum. 20. Cellulose material, characterized in that it is internally bonded with a water-dispersible, water- and alkali-insoluble copolymer of an a,B-ethylenically unsaturated hydrophobic monomer and an ammoniated a,B-ethylenically unsaturated carboxylic acid, and a water-dispersible reaction product of epihalohydrin and ammonia, an alkylamine or an aliphatic polyamine with at least two amine hydrogen atoms per molecule or a mixture of ammonia and an amine. 21. Cellulose material according to claim 20, characterized in that the copolymer contains from 10 to 20% by weight of the carboxylic acid. 22. Cellulose material according to claim 20, characterized in that it is paper. 23. Cellulose material according to claim 20, characterized in that the reaction product is water-soluble and the mole ratio between epihalohydrin and amine is from 0.9 to 2.1 mol of epihalohydrin per moles of amine. 24. Cellulose material according to one of claims 20-23, characterized in that it also contains rosin and alum.